Nick LeClaire’s breakaway goal gave eighth-seed Xavier a stunning 3-2 overtime win over top-ranked and previously undefeated Ridgefield in a Division I boys hockey state tournament quarterfinal game Saturday afternoon at Bennett Rink.

The Falcons (9-10-2) now will play fifth-seed Fairfield Prep in the semifinals on Wednesday at Ingalls Rink in New Haven. Prep blanked 13th-seed Notre Dame-Fairfield, 4-0, in the second quarterfinal Saturday at Bennett Rink.

Xavier’s victory over Ridgefield was bedecked in improbability. The Tigers entered with wins in their first 22 games, were coming off an 8-1 thrashing of Greenwich in the FCIAC championship last Saturday, and looked headed toward the first unbeaten season for a Division I team in 35 years. Xavier, meanwhile, had more losses (10) than victories (nine) and appeared to have minuscule hopes of knocking off Ridgefield.

But the Falcons got a power-play goal from Tom Lynch with 8:09 remaining in the third period to tie the game at 2-2 and then killed off a penalty that began with 28 seconds left in regulation and carried over into the first 1:32 of overtime.

Less than two minutes later, LeClaire pounced on a loose puck near the Ridgefield blue line, blazed down the right wing, and blasted a wrist shot over the glove hand of goalie Sean Gordon for the game-winner.

“He (Gordon) left me an opening and I took it,” LeClaire said about his shot. “Honestly, I was thinking about going low pad for a rebound. But I picked my head up and saw the opening was there and I took it.”

“We knew what we were up against,” Xavier coach Kyle Heins said. “Ridgefield was 22-0; we’re 9-10. We had nothing to lose. If we win we’re heroes; if we lose we’re just another victim.

“With that being said we were prepared … we had a game plan and we executed it,” Heins added. “We just had to shoot pucks and we had to contain them. We had to take the game and bring it right back to them.”

Xavier did that, rallying from a pair of one-goal deficits. After Ridgefield went ahead 1-0 on Matt Walker’s power-play goal with 7:27 left in the first period, the Falcons got the equalizer from Chase Maxwell with 24.9 seconds left in the period.

And after Walker’s second tally gave the Tigers a 2-1 lead early in the third period, Lynch supplied the tying goal on a power play four minutes later.

The Falcons went back on an elongated power play a few minutes later when Walker was assessed a five-minute major penalty. But Ridgefield’s Nicky Cullinan drew a tripping penalty, and the teams played four-on-four for two minutes before Xavier resumed its power play without converting.

Walker was taken down on a breakaway with 28.4 seconds left, giving Ridgefield a man-advantage that extended into the start of overtime. The Tigers applied pressure and shots, but Xavier goalie Jake Woznyk made several nice saves before LeClaire followed with his great individual effort.

“Xavier just outplayed us today,” said Ridgefield coach Shaun Gallagher, whose team finished the season 22-1-0. “I don’t think there’s a part of the game where we had any flow or momentum. We hung in there at times, but we missed some quality opportunities and they buried theirs.

“It wasn’t our game tonight but a lot of that has to do with Xavier’s hustle and effort,” Gallagher added. “Their execution and game plan were very good.”